Abstract

Abstract

Mitochondria isolated from dark-grown seedling-axes of new and old soybeans exhibited differential phosphorylative efficiency when identical cofactors and substrate were provided. The P/O ratio of mitochondria from aged material was 40 to 70% of the new material. Oxygen uptake per unit weight of mitochondrial nitrogen in aged material was 110 to 140% of the new seed.

Addition of serum albumin increased P/O ratio for both materials; sodium fluoride slightly unproved P/O ratio of the new material but had no influence on the old material; and 2,4-dinitrophenol at 10−3M reduced P/O ratio of both materials and supressed oxygen uptake of the old material.

Experimental data indicated that mitochondria from aged seed seems to be endogenously uncoupled and the uncoupling is not due to loss of fatty acids or exogenous ATPase activity. Electron micrograph of the mitochondrial pellets showed a very dense matrix in the mitochondria of germinable but old seeds.

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